It's not about offending MS. It's about not pissing off people who only own XB1. Let's say there's a situation in which media reports that for example, Watch Dogs is notably better on PS4, and XB1 version is missing effects or has framerate problems or lower resolution, and reviews report that. Now, people who only own XB1 are going to say "well, if this version sucks, and they didn't bother spending time to make it work/look better, I'm just going to buy some other game". This mentality is what publishers worry about, and no amount of explaining that spending more time wouldn't make any difference, is going to help.
I think this has happened a lot with PS3 last gen, and publishers took note of it.